With riccia you don't have to do much beyond providing lights and water. It's a real weed IMO, and seems nearly impossible to get rid of once it's in a tank. Luckily it's pretty small and easy enough to pull out once you notice it, but any little bit will grow into a new bunch. You can make some really nice looking carpets with it by covering flat pieces of rock or something with the riccia and then covering in netting, but they'll require remaking after the riccia grows through the netting and floats away. It won't attach to anything so will have to be tied down.